Rock drill



Nov 10, 1931. E, G, GARTIN 1,831,168

Rocx 111111111 Filed March 18, 1929 Patented Nov. 10, 1931 UNITED STATES PATE T emu-.1

man a. GARTIN, or oLAREMoNnnnw HAMPSHIRE, AssIe on 'ro' SULLIVAN cnmnnx COMPANY, A CORPORATION or mnssncnusnms ROCK DRILL Application filed Marcli 18, 1929. Serial No. 347,957.

My invention relates to rock drills and more particularly to hole cleansing means associated with rock drills. An object of my invention is to provide improved means in a percussive rock drill for introducing pressure fluid to a hollow drill steel to blow the cuttings from a hole. Another object is to provide an improved valve device for closing ofi" theicylinder exhaust port of arock drill motor to eflect'a hole blowing operation. A further object is to provide improved means for holding the distribution valve of a rock drill motor in position to eflect continuous admission to the front end of the cylinder, and in connection.

therewith, a valve device for closing a free cylinder exhaust port to blow the cuttings from the hole. Other objects and advantages of the invention will more fully appear during the course of the specification.

In the accompanying drawings I have shown for purposes of illustration two embodiments which my invention may assume in practice.

In these drawings,-

:Fig. 1 represents a central sectional view through a rock drill having, in one illustrative form, my invention associated therewith, the ends of the drilling machine being broken away. f

Fig. 2 is a transverse sectional view'on line 22 of Fig. 1. Fig. 3 is a plan view of a portion of the rock drill showing my improved valve device.

Fig. 4 illustrates a modified form of the.

valve device.

Fig. 5 is a fragmentary view showing a portion of the modified form of valve device, looking at right angles to Fig. 4.

The rock drill shown in Fig. 1 isof the hand rotated type, although it will be understood that my lnvention is equally applicable to drills of the automatically rotated type. In a cylinder member 6 reciprocates a free piston 7 which has a reduced striking portion 8 adapted to strike against the shank 9 of'a hollow drill steel, the bore in said steel being indicated at 10. The'front end of the cylinder is closed by a front head member or chuck housing 11; and at the back end is mounted avalve block12 and a rear head member 13, all of these parts bein secured in assembled relation with the cyIinder by means of the side rods 14 and 15 in a manner well known in the art..- v

The valve block has'means for admitting the air under pressure including an inlet 7 V groove 16 from which pressure fluid is'supplied in one position'ofthevalve to the rear end of the cylinder directly through an axial passage 17, and in the opposite position of the valve, through passages 18and 19 to the front end of the cylinder.. The valve has an annular groovef2O which serves to connect the passage 18 alternately with the supply groove '65 16 and with an exhaust groove 21 which opens to the'atmosphere through a'port 22. The valve is provided with an enlarged flange or' spool 23 which reciprocates in a corresponding bore in the valve block and rearwardlyof this flange has also a reduced portion 24 which is subjected to constant pressure by a passage 25. 'communicatingwith the inlet. When the valve is in the forward position, the space behind the enlarged flange is in communication with the exhaust roove 21 so as'to allow a free reduction oi pres? sure on this area and a small groove 21 connects the space to the rear of this flange con tinuously withythe. exhaust. A throwing passage 26, controlled by the'piston 7, leads from a suitable point ,in the cylinder to the bore inwhich reciprocates the enlarged flange of the valve; One or more free cylinder exhaust ports 27 are provided substantially midway between the ends of the cylinder. In operation,live pressure fluid flows into the inlet groove 16 and, whenthe valve and piston are in the positions shown in Fig. 1', through the axial passage 17and acts onthe rear end of the piston,- The valve is held in the rearward position at this time by the live pressure fluid flowing'to the inlet groove and acting on the end of the valve. The piston is driven forwardly to strike a blow on the drill steel 9 and during itsforward travel the throwing passage 26 is opened whereby pres sure fluid flows from the rearend of thecyl inder to the bore behind the enlarged flange 23 on the valve, thereby overbalancing the 100 on theend surface 24 and" also the pressure acting on the enlarged-flange to hold the valve in its forward position. Air nowflows to the front end of the cylinder and reverses the direction of travel of the piston. The front end of the cylinder is then exhausted through the free exhaust ports-27 and also, after the valve is thrown, through passages '18, '19, groove 20 and passage 22. The valve is thrown :rearwardly by compressioncpressure which acts on the front end ofthe valve and is quickly built up asthe piston covers passage 26.

Duringreciprocation of the piston, acertain amount of pressure fluid will pass through the front end of the cylinder to the bore 10 in the drill steel whenithe piston :is in the rear end ofthe cylinder. However, in drilling fairly deep holes andparticularly in soft formations, the cleansing fluid suppliedin this manner is not suflicient to blow the cuttings from the hole effectively. In order to completely stop the machine and supply live air to the bore inthe drill steel, it is desirable to close offthe free cylinder exhaust port and'forthis'purpose I haveprovided an improved formof manually operated valve device. Anannular groove 28 is cut around the exterior surface of thecylinder substantially midway between the ends thereof so that the free exhaust ports open into this groove.- A cylindrical'band29 preferably made of sheet metal fitsinto this groove so that the exteriorsurfaceof the band conforms to the cylindrical outline of j the cylinder. The ends of this band are provided with suitable lugs30 and 31 for the purpose of receiving a bolt 32 to'tie the ends together and hold the-band in position. A

coil spring 32* may be placed around the bolt in the position shown so as to keep the band always under tension. Any suitable means may be provided for enabling the operator to move the band circumferentially in the groove and for this purpose I have showna knob33. The band has a series of holes 34 so arranged that whenthe knob 33 moves into engagement with oneof'the'side rods 15, all of the exhaust ports are open. When it is desired to close the exhaustxports, the knob is simply shifted to some such position as indicated bythe dottedlines in Fig. 2.

Now it will be clear that the exhaustports maybe closed by the operator when the piston is in the front end of the cylinder or midway between'the ends thereof, and, if this were done, the machine might be stopped in such position that pressure fluid would not be supplied continuously to the front end of the cylinder. In order to insure that, whenever the valve device is moved to close the free exhaust ports, the distribution valve will always be held in its forward position so as to effect continuous supply to the front end of the cylinder, Ihave provided a supplementary passage 34; opening into the'front end of the cylinder and leading to the enlarged bore behind the spool 23 on the valve. The passage 21 to the exhaust. is relatively .restricted so that with the aid of the supplementary passage 346* there will be a substantialpressure acting continuouslyon this enlarged flange.

The valve will thus be shifted and held to its forward position no matter at what point inthe-cycle of the motor piston that the free exhaust port is closed.

The area of the groove 21 is so small as not to affect-normal drilling operations andthe passagef3l will not, with the parts formed asthey are,interfere in any way with normal operations during hammering.

In'the modified form of valve device in Fig. 4 the ends; of the band are formed so as to provide screw threaded plugs 35 and 36'WlITlCl'I are'held together by a suitablenut cally described two forms which my invention may assume in practice, itwill be understoodthat theseforms Of'tllB same are shown for purposes.of'illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire tosecure by Letters Patent is:

1. Ina rock drilling apparatus, a fluid actuated percussive motor having a cylinder and piston, a hollow drill steel actuated by said motor,fluid supply and. exhaust means for said motor including'a free exhaust port through the cylinder wall, said motor having provision for establishing communication between fluid supply and the bore of the hollow drill steel when said exhaust port is closed during fluid supply to the motor, and avalve device for closing said exhaustport at will to effect a hole blowing operation, said valve device being oscillatable about the axisofsaid cylinder'as. an axis.

2. Ina rock ,drilling apparatus, :a fluid actuated percussive motor having a cylinder and a piston reciprocable therein, ashollow drill steel actuated by said motor, longitudinally extending side rods for holding the parts of said motor in assembled relation, pressure fluid supply and exhaust means for said motor including a free exhaust port, said motor having provision for establishing communication between fluid supply and the bore of the hollow'drill steel when said exhaust port is closed during fluid supply to the motor, a valve device for closing said free exhaust port at will to effect a hole blowing operation, said valve device being o'scillatable about the axis of v said motor as an axis, and a projection on said valve device adapted to move into engagement with one of the side rods to determine the open position of said valve.

3. In a rock drilling apparatus, a fluid actuated percussive motor having a cylinder and a piston reciprocable in said cylinder, a hollow drill steel actuated bysaid motor, pressure fluid supply and exhaust means for said motor including a free cylinder exhaust port, said motor having provision for cf fecting communication between the bore of said steel and the interior of the cylinder in a predetermined position of the piston, and

for effecting such positioning, when the cylinder exhaust port is closed, and a valve having a concave seat engaging portion and slidable relative to the cylinder wall for closing off said free exhaust port at will so as to prevent discharge of pressure fluid therethrough thereby to effect a hole blowing operation. h

4:. In a rock drilling apparatus, a fiuidactuated percussive motor having a cylinder and piston reciprocable therein, a hollow drill steel actuated by said motor, fluid distribution means for said motor including a free cylinder exhaust port, said motorhaving provision for effecting communication between thebore of said steel and the in terior of the cylinder in a predetermined position of the piston, and for effecting such positioning when the cylinder exhaust port is closed, and a valve device comprising a member extending around said cylinder and 6 slidable relative to the cylinder wall for closing said exhaust port at will so as to prevent discharge of pressure fluid therethrough thereby to effect a hole blowing operation.

5. In a rock drilling apparatus, a fluid actuated percussive motor having a cylinder and a piston reciprocable therein, a hollow drill steel actuated by said motor, fluid distribution means for said motor including a free cylinder exhaust port, said motor having provision for effecting communication between the bore of said steel and the interior of the cylinder in a predetermined position of the piston, and for effecting such positioning when the cylinder exhaust port is closed, a valve device comprising a member extending. around said cylinder and slidable relativeto the cylinderwall for closing said exhaust port at will so as toprevent disradially projecting knob on said member,

whereby the same maybe sliiftedfrom one position to another.

6. In a rock drilling apparatus, a fluidactuated percussive motor} having a. cylinder and a piston reciprocable therein, a hollow drill steel actuated by said motor, fluid distributionmeans for effecting supply and-exhaust of motive fluid to and from said cylinder including a, free exhaust-port in the wall of said cylinder, said motor having provision for effecting communication between the bore of said steel and the interior of the cylinder in a predetermined position of the piston, and for effecting such positioning when the cylinder exhaust port is closed, a valve having a curved seat and slidable relative to said cylinder wall for covering said exhaust port at will so as to prevent discharge ofpressure fluid therethrough thereby to effect a hole blowing operation, said seat conforming in curvature to the surface of a cylinder struck from the axis of the 'motor cylinder, and

means extending around said cylinder for holding said valve in position.

In a rock drilllng apparatus, a fluld actuated percussive motor having a cylinder and piston reciprocable in said cylinder, a v

hollow drill steel actuated by said motor, fluid distribution means for effecting supply and exhaust of motive fluid to and from said cylinder including a free exhaust port in the wall of said cylinder, the exterior of said cylinder having a groove formed therein communicating w th said exhaust port, and

a band extending around said groove and oscillatable therein, said band having an aperture adapted to be alined with said exhaust vport, saidband acting when shifted away from said position to close said exhaust port for effecting a hole blowing operation.

8. In a rock drilling apparatus, the combiv nation specified in claim 7 wherein there is further provided means for adjustably tensioning said band to hold the same in engagement with said groove.

9. In a rock drilling apparatus, a fluid actuated percussive motor having a cylinder and a piston reciprocable in said cylinder, a hollow drill steel actuated by said motor, fluid distribution means for effecting supply andexhaust of motive fluid to and from said cylinder including a distribution valve and a free cylinder exhaust port, said distribution valve having a surface adapted to be subj ected to pressure fluid for holding the valve in po sition to admit motive fluid to the front end machine, a passage arranged to establish cominunication between said surface and the front end of the cylinder, said passage opening into the cylinder independently of said free cylinder exhaust port andnearer' the for- Ward end of the cylinder than said exhaust port, and a valve device for closing said free cylinder exhaust port.

10. In a rock drilling apparatus, the construction set forth in claim 9 wherein said valve device comprises a member extending around said cyiinder and oscillatable about the axis thereof to effect closing of the cylinder exhaust port.

In testimony whereof I aflix my signature.

- ELMER Gr. GARTIN. 

